1. Field of the Invention
The present invention relates generally to static mixers and, more particularly, to the coupling of a static mixer to a cartridge device.
2. Description of the Prior Art
Static mixers and their connection to cartridge devices in general are well known. Static mixers are adapted for connection to cartridges containing more than one chamber, with each chamber containing a different material. The static mixer receives the materials and mixes them before discharging the mixed materials onto a desired surface. For example, U.S. Pat. No. 5,080,262 issued Jan. 14, 1992, discloses a structure in which two materials are stored in separate chambers in a cartridge. As the materials are extruded from the cartridge, one material is moved into an annular orifice which surrounds a central cylindrical orifice for the other material. A static mixer is provided which screws into the cartridge and has various walls and edges at different levels and of complex shapes required to mate with complementary walls and edges of the coaxial end of the cartridge forming continuations of the annular orifice and the central cylindrical orifice. The complex structure renders this static mixer very expensive and after each use is generally necessary to dispose of the mixer since the materials harden in the mixer.
U.S. Pat. No. 4,767,026 issued Aug. 30, 1988, describes a mixer having a double walled baffle positioned in a common orifice to keep the materials from the cartridge separated as they are extruded into the mixer. Mixing in this device takes place at the end of the baffle which is at the end of the cartridge. Typically, after extrusion for a particular use is completed, the static mixer is retained as a cap until the next use. However, since there is no particular structure to keep the materials from mixing at the end of the baffle, the backcuring of the materials upstream of the static mixer will cause the materials to harden and the cartridge will have to be discarded together with any unused materials.
Upon manufacture and prior to use with a static mixer, a closure cap is used to cover the cartridge. The closure cap prohibits the extrusion of materials from the cartridge prior to initial use. An example of a closure cap is described in U.S. Pat. No. 5,137,182 issued Aug. 11, 1992. This patent discloses a closure cap for the nozzle orifice of a dispensing cartridge. This cap has a base including a number of stoppers projecting from the base. The stoppers each have a number of fillets spaced along their length with one fillet at the junction between the stopper and the base. The stoppers fit into the orifices of a dispensing cartridge forming a pressure seal. The base also has anchoring devices projecting from its sides for securing to the cartridge.
U.S. Pat. No. 3,506,157 issued Apr. 14, 1970 discloses a two piece closure cap. This cap includes an inner piece having two prongs for placement within the bores of a cartridge and a rotatable portion having threads on an inner side thereof. The cap screws onto the neck of the container. Another type of closure device is described in U.S. Pat. No. 3,143,255 issued Aug. 4, 1964. This device includes a deformable plug member which engages an opening in the wall of the container. The plug contains a passageway allowing for the container contents to be dispensed when in an open position, and blocked when in a closed position. Finally, U.S. Pat. No. 4,974,756 issued Dec. 4, 1990 discloses a dispensing container and cap assembly. The cap includes two protrusions for orienting the cap so that each closure portion contacts the same outlet each time the cap is coupled to the container.
While each of the caps are useful, it is desirable to have a single coupling arrangement on the cartridge which would connect to both a static mixer and also for connection to a closure cap. The connection must keep material from the cartridge chambers separate from each other until they reach the static mixer. The static mixer will then combine the materials in the correct proportions. The connection between the static mixer and cartridge is needed which also provides a tight fit not allowing material to smear between the static mixer and cartridge. Also needed is a way of capping the cartridge prior to use with the static mixer to account for uneven amounts of material within the chambers of the cartridge and for parallelizing the plungers within the chambers.
It is, therefore, needed to produce a dispenser which solves the aforementioned problems and provides improvements over the presently known connections between static mixers and cartridges.